nanoDLP

sgraber

Member

From: Indiana

Registered: 2016-03-11

Posts: 54

Website

NanoDLP crashes when model too large

I'll preface this by saying I'm running NanoDLP on a Raspberry Pi 2, which could be causing my problem to begin with, but I thought I'd check anyhow. 

I have noticed that if I upload too large of a model stl (in my case a 350MB file) that this will crash my Pi when NanoDLP starts slicing it.  The only way I can get my NanoDLP to come back up is to reboot, immediately shut down the NanoDLP instance, then manually remove the offending STL from printer/database/plates.json and /printer/public/.  Rebooting the Pi then fixes the problem.  I was curious if there is an upper limit?

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,541

Re: NanoDLP crashes when model too large

Interesting topic.

OS itself takes around 124MB memory. (900MB=1024-120)
Usually nanodlp takes under 1.5% of RPi memory (~15MB) to run. (885MB)
To slice a STL file, it required to load whole file data into the memory.
Lets say you have 350MB file, we need to load 36 Bytes useful data for each 50 Bytes.
Means we are loading 252MB useful data. We need to consider 50% overhead in this stage due to GC and etc. (507MB=885-378)

Tricky part is slicing. How many of these triangles will get used by our cutter. If the model is highly detailed and details happens to be in around same height. I have seen some modelling programs creating very tall vertexes.
Lets say 10% vertexes will be used for highly detailed heights, to keep new points by slicer for each layer we will need around 25MB (if our 10% assumption is correct) But to speedup things we do slicing with up to 4 threads. 4*25MB (407MB=507-25*4)

For each FULLHD image we need 8MB memory allocation + 50% overhead (359MB=407-12*4)
Rendering engine, anti-aliasing render engine (even-though I believe ours is highly effective) and all graphical tricks at-least will takes 5 times more memory than previous step (119MB=359-12*5*4)

Considering memory allocated for each image would not get released instantaneously, and will require GC sweep. I believe 119MB empty memory is dangerously low.

I think 250MB STL file will be safe to use except special conditions.

If you need to use larger files, use SLC format. I tend to use 1.5GB SLC files with nanodlp. For SLC files only limitation is SD storage size.

sgraber

Member

From: Indiana

Registered: 2016-03-11

Posts: 54

Website

Re: NanoDLP crashes when model too large

Do you have a recommendation for a SLC program for converting STLs?  I seem to recall seeing a recommended one on the NanoDLP homepage, but it's gone.

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,541

Re: NanoDLP crashes when model too large

asiga stomp

sgraber

Member

From: Indiana

Registered: 2016-03-11

Posts: 54

Website

Re: NanoDLP crashes when model too large

asiga stomp

Awesome; thank you!    Wow, those sliced models upload fast and convert fast compared to uploading a STL or SVG!  I'm a convert.

grizfyrfyter

Member

Registered: 2017-05-02

Posts: 17

Re: NanoDLP crashes when model too large

I love when i find the answer to a problem without having to ask it. Thanks!

sgraber

Member

From: Indiana

Registered: 2016-03-11

Posts: 54

Website

Re: NanoDLP crashes when model too large

FWIW I pretty much exclusively use Asiga Stomp to make .slc files now which I then upload to NanoDLP.

mickymax75

Member

Registered: 2017-10-31

Posts: 29

Re: NanoDLP crashes when model too large

Hi guys,
I got same problem of huge file broken for directly upload to nanodlp.
So I used Netfabb....sliced the stl and afteruploaded as palte on Nanodlp.
everything goes right!
But printed object is deformed.....x-y-z The printed object is elongated and squeezed????
Do you any issue about that?

thanks
Mic

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,541

Re: NanoDLP crashes when model too large

Try latest version, if you have enough space on SD card, system would not crash

mickymax75

Member

Registered: 2017-10-31

Posts: 29

Re: NanoDLP crashes when model too large

Hi Shain
Upgraded to latest stable version, a lor of freespace avaible...and tryed to upload a stl file of 280mb....but got same error:
Error post file issue read tcp ...addresses...i/o timeout

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,541

Re: NanoDLP crashes when model too large

Try wired connection.

mickymax75

Member

Registered: 2017-10-31

Posts: 29

Re: NanoDLP crashes when model too large

Do you mean ftp file into raspberry directly?
My workround is using laptop and print from it with CW.
But it means pc is all night long on and connected to printer.

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,541

Re: NanoDLP crashes when model too large

I mean connect your RPi through ethernet cable not wireless, see if it makes any difference.